The present invention relates generally to semiconductor devices and methods of manufacturing the same, and in particular to semiconductor devices including contact plugs and lines and methods of manufacturing the same.
An overlay margin between a metal line and a contact plug becomes smaller as cell area decreases. This decrease in cell area is directly attributable to the increase in the degree of integration of memory devices. As the overlay margin becomes smaller, there is a high probability that metal lines and contact plugs may be misaligned because the metal lines are formed after forming the contact plugs.
If metal lines and contact plugs are misaligned as described above, the distance between a contact plug and a metal line adjacent to the contact plug decreases. The distance between the contact plug and the adjacent metal line may become smaller than the critical distance at which leakage current does not occur between adjacent conductive layers. As a result, a leakage current may be generated between the contact plug and the adjacent metal line.
Furthermore, unwanted capacitance between metal lines increases as the distance between adjacent metal lines decreases.